Dogs will steal your food if they think it's dark enough for you not to notice.
Take 84 dogs. Put each one in a room with food on the floor and instruct
the dog to leave it alone. Try it in a dark room and a nicely lit room.
What will happen? According to a study in the journal Animal Cognition,
“the dogs were four times as likely to steal the food — and steal it
more quickly — when the room was dark,” National Geographic
reported. The study leader, Juliane Kaminski of the University of
Portsmouth in England, explained how this shows us that dogs know a
thing or two. “It implies dogs understand the human can’t see them,
meaning they might understand the human perspective,” she said in a news release.